The Importance of Visual Field Tests
Visual field testing is one of the key diagnostic tests for glaucoma. During this test, the patient looks straight ahead into a lighted bowl and then responds every time a light is flashed and perceived at different point of one’s peripheral (or side) vision. This helps draw a map of the patient’s field of vision.
When you test vision on an eye chart, only the central vision is tested. But in glaucoma, even in cases when the IOP appears stable, in most cases the field of vision is the first to be affected. By the time central vision is impacted, glaucoma may already be far advanced with almost all peripheral vision lost.
Visual field testing devices all incorporate an internal computer with the ability to store, print, and transmit important patient data. There are many variables involved in obtaining reliable results and it often takes several tests before a reliable initial baseline is established. This is a recognized phenomenon. Further field tests are then performed periodically, their frequency depending on other factors but at least once a year, to detect any new field defects, to visually compare a sequence of reliable field tests, and to look for changes in the field defect pattern that are indications of how the disease is progressing.
The final report on the printout is a dramatic rendering and quick overview of the patient’s field of vision. It’s a visual graph of each eye’s field of vision from the central degrees all the way out to the farthest peripheral extent of the field. The degrees of the field are shown in boxes that may be filled in gray to denote mild to moderate defects in the field, or black to reflect total loss.
It is impossible to evaluate the state of your vision without a true visual field test conducted in the eye doctor’s office. During regular eye checkups the doctor will also examine the optic nerve and measure the IOP.
TGF Urges Eye Exams to Detect Glaucoma Early
Some 3 million Americans have glaucoma. Unfortunately, half of them are unaware they have the potentially blinding disease because they have no symptoms. “Too many people believe they can tell if they’re developing glaucoma,” says Dr. Gregory K. Harmon, Chairman of The Glaucoma Foundation and author of What Your Doctor May Not Tell You About Glaucoma. “That’s one dangerous myth among numerous others,” he adds. Here are a few other myths.
All people with glaucoma have elevated intraocular pressure (IOP).
Elevated IOP is a risk factor for glaucoma and is not the disease itself. There are more than forty different types of glaucoma, and not all of them are associated with elevated IOP. Glaucoma specialists believe that some forms of glaucoma are strongly related to vascular changes and impaired “nutrition” (poor blood flow) to the optic nerve. The common thread among all glaucoma is damage to the optic nerve rather than elevated IOP.
Only old people get glaucoma.
Though frequency increases with age, glaucoma can strike at any time in a person's life. Approximately one in 10,000 babies is born with glaucoma and children between the ages of four and ten may develop a form of the disease called late congenital glaucoma. For those affected between ages ten and 35, the most common causes are hereditary disorders.
Glaucoma is curable.
Glaucoma is a chronic condition that needs ongoing treatment and monitoring. If damage has occurred, at this time it is irreversible. Early detection and treatment minimizes the risk of permanent vision loss. With ongoing research and the help of many foundations like this one, hopefully one day this will no longer be a myth and we’ll have a cure.
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TGF 2015 INTERNATIONAL THINK TANK
The Glaucoma Foundation has announced that the topic for its 22nd Annual Optic Nerve Rescue and Restoration Think Tank in September is “Regenerative Medicine for Cornea and Trabecular Meshwork.”
The Glaucoma Foundation Think Tank is unique in glaucoma research. Its goal is to explore areas of the future which have not previously been the subjects of major conferences. Each year, participants include clinician-scientists, researchers in glaucoma, researchers in other areas of the eye, and people totally uninvolved with the eye (e.g. nanotechnology, stem cells, other organisms, and gene therapy) in order to cross-fertilize and to identify important areas for future research and funding.
Previous Think Tanks have opened new research directions in the field and attracted some of today's leading researchers in glaucoma. They have resulted in important interdisciplinary exchanges, identification of important new areas of investigation, establishment of new collaborations, prioritization of a set of recommended areas of research, and in many cases, grant applications that have been funded by the Foundation.
This year’s Think Tank enters a new area, moving partly away from glaucoma yet tying together cornea and trabecular meshwork. Its focus is on the repair and regeneration of the anterior segment. A report on the Think Tank will appear in the next e-newsletter.
Are Your RX's Ready for Traveling?
It’s especially important for glaucoma patients to follow-through with their treatment plans – even while traveling. Here’s a checklist from The Glaucoma Foundation to help you prepare for a safe and healthy trip:
And here are a few final eye care
- Make a list of all medications you normally use, noting each prescription dosage, the medication’s trade name as well as the generic name for the drug. Generic names are especially important if you are traveling out of the country, where drug makers may use different names from those in the U.S.
- Bring a sufficient supply of each medication for the length of your trip, and talk to your doctor in advance about getting extra prescriptions, just to be safe.
- Pack your medications in their original drugstore containers rather than in pill cases or other unlabeled bottles.
- Never pack medications in checked baggage, which can be lost or stolen. Put them in your carry-on bag and always keep that with you.
- Store all medications in a dark, cool place – for example, among or inside clothing.
- If you’re crossing time zones, ask your doctor how you should take your medication. Many doctors recommend adapting your schedule to the local time at your destination, and not worrying about a missed dose due to time change. This can simplify your regimen during your stay as well as on your return.
- Traveling on a plane will not affect your eye pressure (IOP) – it is a controlled atmosphere and compensates for changes in altitude. But open medication bottles carefully when you’re first back on land.
- The air on airplanes is very dry. If you wear contact lenses, frequently apply rewetting solution.
- Be safe rather than sorry. If you wear prescription eyeglasses, take an extra pair with you.